IHttpTraceContext::QuickTrace Method

Article
03/09/2018

Writes a message to the IIS trace log.

Syntax

virtual  
    HRESULT  
    QuickTrace(  
        IN PCWSTR   pszData1,  
        IN PCWSTR   pszData2 = NULL,  
        IN HRESULT  hrLastError = S_OK,  
        IN UCHAR    Level = 4  
    ) = 0;

Parameters

Parameter	Description
`pszData1`	A message to log.
`pszData2`	A second message to log.
`hrLastError`	The `HRESULT` to log. The default is S_OK.
`level`	The trace level. The possible values are 1 through 7. The default is 4 (TRACE_LEVEL_INFORMATION). For more information, see the Remarks section.

Return Value

An HRESULT. Possible values include, but are not limited to, those in the following table.

Value	Description
S_OK	Indicates that the operation was successful.

Remarks

Event trace levels 1 through 5 correspond to Event Tracing for Windows (ETW) trace levels. For more information about these trace levels, see the EVENT_TRACE_HEADER structure. You can also use trace level 6 (defined as HTTP_TRACE_LEVEL_START in the Httptrace.h header file) and trace level 7 (defined as HTTP_TRACE_LEVEL_END in Httptrace.h).

Example

The following example demonstrates how to use the IHttpRequest::SetUrl method to change a requested URL to another URL and log the change with the QuickTrace method.

You must enable Failed Event Request tracing to see the event.

int _tmain(int argc, _TCHAR* argv[])
{
    printf("It works!");
    return 0;
}

#define _WINSOCKAPI_
#include <windows.h>
#include <sal.h>
#include <httpserv.h>

// Create the module class.
class MyHttpModule : public CHttpModule
{
public:
    REQUEST_NOTIFICATION_STATUS
    OnBeginRequest(
        IN IHttpContext * pHttpContext,
        IN IHttpEventProvider * pProvider
    )
    {
        UNREFERENCED_PARAMETER( pProvider );

        // Retrieve a pointer to the request.
        IHttpRequest * pHttpRequest = pHttpContext->GetRequest();

        // Test for an error.
        if (pHttpRequest != NULL)
        {
            // Specify an OPTIONS request method.
            HRESULT hr = pHttpRequest->SetHttpMethod("OPTIONS");
            // Test for an error.
            if (FAILED(hr))
            {
                // Set the error status.
                pProvider->SetErrorStatus( hr );
                // End additional processing.
                return RQ_NOTIFICATION_FINISH_REQUEST;
            }
        }

        // Return processing to the pipeline.
        return RQ_NOTIFICATION_CONTINUE;
    }
};

// Create the module's class factory.
class MyHttpModuleFactory : public IHttpModuleFactory
{
public:
    HRESULT
    GetHttpModule(
        OUT CHttpModule ** ppModule, 
        IN IModuleAllocator * pAllocator
    )
    {
        UNREFERENCED_PARAMETER( pAllocator );

        // Create a new instance.
        MyHttpModule * pModule = new MyHttpModule;

        // Test for an error.
        if (!pModule)
        {
            // Return an error if the factory cannot create the instance.
            return HRESULT_FROM_WIN32( ERROR_NOT_ENOUGH_MEMORY );
        }
        else
        {
            // Return a pointer to the module.
            *ppModule = pModule;
            pModule = NULL;
            // Return a success status.
            return S_OK;
        }            
    }

    void Terminate()
    {
        // Remove the class from memory.
        delete this;
    }
};

// Create the module's exported registration function.
HRESULT
__stdcall
RegisterModule(
    DWORD dwServerVersion,
    IHttpModuleRegistrationInfo * pModuleInfo,
    IHttpServer * pGlobalInfo
)
{
    UNREFERENCED_PARAMETER( dwServerVersion );
    UNREFERENCED_PARAMETER( pGlobalInfo );

    // Set the request notifications and exit.
    return pModuleInfo->SetRequestNotifications(
        new MyHttpModuleFactory,
        RQ_BEGIN_REQUEST,
        0
    );
}

Requirements

Type	Description
Client	- IIS 7.0 on Windows Vista - IIS 7.5 on Windows 7 - IIS 8.0 on Windows 8 - IIS 10.0 on Windows 10
Server	- IIS 7.0 on Windows Server 2008 - IIS 7.5 on Windows Server 2008 R2 - IIS 8.0 on Windows Server 2012 - IIS 8.5 on Windows Server 2012 R2 - IIS 10.0 on Windows Server 2016 Technical Preview
Product	- IIS 7.0, IIS 7.5, IIS 8.0, IIS 8.5, IIS 10.0 - IIS Express 7.5, IIS Express 8.0, IIS Express 10.0
Header	Httpserv.h

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